Infections as a potential long-term risk following childhood leukemia

Leukemia is the most common childhood cancer. While infections are a frequent and potentially severe complication while on treatment, less is known about the risk for infections following therapy completion. In this article, we propose that leukemia survivors might be at increased risk of infections following therapy completion than the general population, independently of potential confounders such as age, sex and Down syndrome. This association is conceivably due to several factors. First, therapy-induced immune dysfunction of both the humoral and cellular compartments appears to last for several years following anti-cancer therapy and after hematopoietic stem cell transplantation. Second, clinical and epidemiological research has shown leukemia survivors are disproportionally affected by comorbidities related to leukemia treatment and its complications, such as diabetes and obesity, which may induce secondary immunodeficiency and infections. Last, differences in health-related behaviors between leukemia survivors and the general population (such as re-vaccination practices) may affect the baseline risk of infections. Although under-represented in the epidemiological literature as a possible late effect of childhood leukemia and its treatment, it is plausible that leukemia survivors are at increased risk of infections for several years when compared to the general population and their siblings. Further research is needed to empirically test these hypotheses.